Reversing transmission mechanism.



71 2172 ess as COLUMBIA PLANDURAI'H COHWASHINGTCIYG', I) c,

Patented Aug. 27, 1912.

NORMAN T. HARRINGTON, 0F LANSING, MICHIGAN.

REVERSING TRANSMISSION MECHANISM.

To all whom it may concern:

Be it known that I, NORMAN T. HARRING- 'roN, a citizen of the UnitedStates of America, residing at Lansing, in the count-y of Ingham andState of Michigan, have invented certain new and useful Improvements inReversing Transmission Mechanism, of which the following is aspecification, reference being had therein to the'accompanying drawings.

The invention relates to transmission mechanism and is more particularlydesigned for use in connection with traction engines having for itsobject the avoidance of a divided shaft construction, and also theobtaining of a simple, compact and durable form of reversingtransmission mechanism.

In the drawings,Figure 1 is a longitudinal section through thetransmission mechanism showing the cont-rolling rock arm in sectionalelevation; and Fig. 2 is a detail sectional view.

In the present state of the art various constructions of reversibletransmission mechanism have been made in which opposed bevel gear wheelsare arranged upon opposite sides of a pinion and are adapted to bealternatively engaged therewith.

The present invention relates to mechanism of this type but theconstruction is such that greater strength and durability of parts areobtained.

In detail, A is the driving shaft upon which is mounted the bevel pinionB.

C is a shaft perpendicular to the shaft A and extending across the endthereof.

D and D are bevel gear wheels mounted upon the shaft C upon oppositesides of the pinion B and having their toothed faces opposed. The gearwheels D and D are rigidly mounted upon the shaft and keyed thereto asindicated at E, and as the shaft 0 extends unbrokenly to its supportingjournals, a very rigid and strong construction is obtained.

F is a yoke frame having formed therein, bearings for theshafts A and Cand embracing the gear wheels D and D.

H is a rocker arm mountedin the yoke frame F between the gear wheels Dand D and preferably bifurcated to embrace a block member I sleevedabout the shaft. This Specification of Letters Patent.

Application filed July 15, 1911.

Patented Aug. 2'7, 1912. Serial No. 638,739.

block member is preferably concaved at its opposite ends to engageconvex bearings J on a thrust bearing K extending to the adjacent gearwheel D. The arrangement is such that when the rocker H is shifted itwill move the block I longitudinally of the shaft C and through thethrust bearings K will transmit its motion to the gear wheels D, D andshaft C, which are moved bodily, thereby alternatively engaging thegears D and D with the pinion B.

' To operate the rocker H a suitable operating connection is providedbut it is essential that the movement should be confined within exactlimits as otherwise the gears will be jammed against the pinion andimperfectly engaged therewith, which would be objectionable. I haveobtained this exact movement by an operating connection preferablyconstructed as follows: L is a rock shaft upon which the rocker H ismounted and M is a rock arm or lever for actuating the shaft L. N is anextension of the rock arm M which engages a socket O in the end portionthereof and is pivotally secured thereto at P. Q and Q are setscrews inthe socket 0 upon opposite sides of the pivot extension N and adapted tobe adjusted for variably limiting the independent movement of saidextension. R is an operating device for rocking the extension N which,as shown, comprises a crank having the pin S thereof engaging a slidablehearing T in a socket at the end of the extension member N.

With the construction as described, the rotation of the crank R willimpart a rocking movement to the lever M and extension N thereof. Thismovement is transmitted through the shaft L to the rocker H and from thelatter to the thrust bearing, bevel gears and shaft. The amount of throwof the crank R is such as to move the gear wheels D and D a greaterdistance than necessary to engage the same alternatively with the pinionB. However, this excess of movement is avoided by providing lost motionbetween the rockable lever M and the extension N thereof and this isaccomplished by an adjustment of the said screws Q and Q. Thus thegreater the space between the extension N and the set-screws the greaterthe amount of lost motion which correspondingly diminishes the amount ofmovement transmitted to the member M. It will be understood that byproper adjustment of the set-screws Q and Q, the movement imparted tothe gear wheels D and D can be so limited that each gear wheel will comeinto full mesh with the pinion B but will avoid bind ing thereagainst.

As usually constructed, bevel gear wheels when in mesh with each otherare so con structed that lines projecting from the inner and outer facesof the teeth will coincide with the point of intersection of the axes ofsaid gears. Thus said inner and outer faces are in angular relation toeach other and consequently the outer faces of the two gears are inangular relation. It is evident therefore that if the gears are engagedand disengaged all portions of the teeth will not simultaneously enterinto engagement, but said engagement will start from single points inthe gear teeth. The effect of this is to increase the liability ofbreaking of the teeth when they are moved into engagement. In myconstruction I have avoided this by changing the angle of a portion ofthe outer faces of the teeth so as to be the same in both of theintermeshing gears, and therefore, to permit of simultaneous engagementand disengagement of all port-ions thereof. As shown each tooth U has aportionVof its outer face cut-01f to an angle parallel to its inner facewhich will produce the desired result.

With the construction as described in operation the mechanism may at anytime be reversed by manipulation of the crank R which will shift therocker arms N and M which in turn operate the rocker H and shift thegear wheels B and B. During this movement the teeth U of the gear wheelswill be brought into mesh with the corresponding teeth of the pinionB,but on account of the angle of the portions V the teeth will beengaged without danger of breakage.

What I claim as my invention is:

1. In a transmission mechanism the combination with a rotatable bevelpinion, of opposed bevel gear wheels upon opposite sides of said pinion,a longitudinally adjustable shaft upon which said wheels are fixedlymounted, means for adjusting the shaft to alternately engage the pinionwith said wheels, and adjustable means for limiting the movement of saidfirst-mentioned means to effect a predetermined engagement of therigidly mounted, a member between said bevel gear wheels having a thrustbearing engagement therewith, a rockable member for engaging said memberintermediate the gear wheels, and adjustable means for exactlydetermining the movement imparted to said rocker.

3. In a transmission mechanism, the combination with a rotatable bevelpinion, of a pair of opposed bevel gear wheels arranged upon oppositesides of said bevel pinion, a shaft upon which said bevel gear wheelsare rigidly mounted, journal bearings for said shaft permitting thelongitudinal adjustment thereof, a member between said bevel gear wheelshaving end thrust bearing engagement therewith, a rocker engaging saidmember, means for operating said rocker, and adjustable means forexactly determining the movement of said rocker to produce the properengagement of said bevel.

4. In a transmission mechanism, the combination with a rotatable bevelpinion, of opposed bevel gear wheels arranged upon opposite sidesthereof, a shaft upon which said bevel gear wheels are fixedly mounted,bearings for said shaft permitting the longitudinal adjustment thereof,a member sleeved about said shaft intermediate said gear wheels, thrustbearings between said sleeve and gear wheels, a rockable member having aportionembracing said sleeve, and means for actuating said rockablemember between exact limits of movement, said limits being adjustable toeffect a full engagement of said bevel gear wheels with said pinion.

5. In a transmission mechanism, the com bination with a rotatable bevelpinion, of opposed bevel gear wheels arranged upon opposite sides ofsaid pinion, a shaft upon which said bevel gear wheels are fixedlymounted, a rockable member for shifting said shaft and gear wheels toalternately engage the latter with said pinion, a member for actuatingsaid rockable member adapted to impart to the latter a movement inexcess of that needed for the shifting of said gear wheels, and meansfor variably introducing lost motion in the operating member to limitthe actuation of said rock-able member.

6. In a transmission mechanism, the combination with a rotatable bevelpinion, of opposed bevel gear wheels arranged upon opposite sides ofsaid pinion, a shaft upon which said gear wheels are fixedly mounted, arockable member for adjusting said shaft and gear wheels to alternatelyengage the latter with said pinion, a rockable actuating arm for saidrockable member, an extension of said actuating arm, means for actuatingsaid extension to impart to said actuating arm a greater movement thannecessary for the adjustment of said bevel gear wheels, and anadjustable connection between said extension and actuating member forintroducing a variable degree of lost motion therebetween.

' 7 In a transmission mechanism, the combination With a rotatable bevelpinion, of a bevel gear Wheel arranged upon one side of said pinion andadjustable into and out of mesh therewith, said pinion and gear Wheelbeing provided With teeth having portions of their outer faces parallel,whereby all points in said parallel portions will simultaneously enterand leave engagement with the teeth of the opposite member.

In testimony whereof I afiix my signature in presence of two Witnesses.

NORMAN T. HARRINGTON.

Witnesses:

GEORGE F. KNoWLEs, L. E. CHAPMAN.

Copies of this patent may be obtained for five cents each,

by addressing the Commissioner of Patents,

Washington, D. G.

